SOLID SCIENCE: 

By Dr. Tianhai Yan

A dairy cow needs enough nutrients to meet her requirements for basal activity, milk production, body weight gain and pregnancy. These demands are determined by calculation of amount of feed energy requirements using dairy cow energy rationing systems.

The largest requirement for a lactating dairy cow is for milk production – the requirement is estimated from milk energy output and the efficiency of utilization of metabolisable energy (ME) for lactation (k_l). The next major demand is for maintenance of basal activity which is quantified as ME requirement for maintenance (ME_m).

Energy rationing systems currently adopted across Europe are developed for the ‘average’ dairy production in a national herd level. These systems may not be fully applicable for dairy cows managed under low input and organic dairy farming. Tasks 2.4 and 3.3 of this SOLID project were therefore designed to evaluate if there was any difference in energy utilization between Holstein-Friesen (HF) and other genotypes of dairy cows and between low and high input systems, respectively. The data used to address these objectives were derived from 1050 respiration calorimeter measurements at the Agri-Food and Biosciences Institute (AFBI) in UK. Calorimeter chambers can be used to accurately measure energy intake and outputs including heat production and methane energy output.

The objective of Task 2.4 was to evaluate the effects of cow genotypes on ME_m and k_l values. The first test was to compare these two variables between Norwegian Red cows (NRC) and HF crossbred with NRC or Jersey. The statistical analysis found that the average ME_m and k_l values were similar between the two genotypes. The data from HF crossbred and NRC were then pooled and subsequently used to compare with HF dairy cows. The statistical analysis also reported no significant difference in ME_m or k_l between the two groups. These results indicate that when cows are fed for a similar level of milk production, HF crossbred and NRC cows can use feed energy with a similar efficiency to HF cows.

The task 3.3 was designed to evaluate if there was any significant difference in ME_m or k_l for dairy cows managed under different input systems. The whole AFBI calorimeter dataset was divided into four groups according to forage proportion in the diet (FP, dry matter basis), namely FP<30%, FP=30-59%, FP=60-99% and FP=100%. The statistical analysis demonstrated that while k_l values remained similar among the 4 groups, increasing dietary FP significantly increased ME_m values although the difference between FP=60-99% and FP=100% did not reach significance. The cows offered high forage diets may spend more time and effort for feed intake and rumination, and thus require more energy to maintain their basal activity when compared with those offered high concentrate diets.

The results from these two tasks demonstrate that dairy cows managed under low input or organic farming regimes may require more feed energy for maintenance of their basal activity than those reared in high input systems.

Using the current energy feeding systems to ration dairy cows managed under low input systems may somewhat underestimate their feed requirement.

There is a need to upgrade the current energy rationing systems to implement the present finding for low-input and organic dairy farming.

Marco Horn, a young livestock scientist from Austria, did his Ph.D. as part of the SOLID project which gave him a unique opportunity to become part of an international network of more experienced livestock scientists.

By Ulla Skovsbøl

A number of young scientists have benefitted from being involved in research in organic and low input farming systems within the SOLID project. One of them is Marco Horn – a young livestock scientist from Austria who did his Ph.D. at the University of Natural Resources and Life Sciences in Austria as part of the SOLID project. At the annual SOLID meeting in Granada in May 2015, he agreed to give an interview about his SOLID experience:

Marco, why did you become involved with SOLID?

Marco Horn: I did my Masters at the Department of Sustainable Agricultural System. It was related to organic dairy farming and I was keen to get involved in research on genotype by environment interaction. So, I was happy when the Head of Department Werner Zollitsch asked me to be involved in SOLID.

So what was the topic of your Ph.D.?

Marco Horn: In my Ph.D. I compared different Alpine dairy cow types with regard to their suitability for low input dairy farm systems.

Why did you take an interest in low-input farming?

Marco Horn: There has been a focus on low input farming in Austria during recent years and at my Institute there were teachers giving lectures on that topic during my Masters study. It made me curious and I found it quite interesting, so I was happy to get an opportunity to contribute to building up new knowledge in that field.

How was it to be a part of this extended network of scientists?

Marco Horn: I enjoyed it a lot because scientific work depends on sharing knowledge and discussing it, and a project like SOLID is the perfect platform for doing it. The experiments we did in Austria were also conducted in a similar way in Ireland and Finland and we could discuss our findings in our transnational group. However, by also participating in the annual SOLID meetings you could get the feedback from all the other partners, some of whom are dealing with life cycle assessment, others with consumer interviews etc. and they can often contribute with valuable input from new perspectives. I enjoyed those discussions a lot.

How did that add value to your own research?

Marco Horn: As a researcher you have your own hypothesizes, opinions and ideas, but they have to be discussed and challenged. It´s very valuable when somebody else is questioning your conclusions from a totally different angle. It qualifies your research a lot.

So what are you doing now?

Marco Horn: I finished my Ph.D. in December 2014 and now I work as a dairy consultant for the Austrian Chamber of Agriculture.

How can you use the knowledge you gained from SOLID and your Ph.D.?

Marco Horn: Now, it’s really about using everything we learned at the livestock science institute, but in particular, in the SOLID project the focus was not only on a very specific aspect of dairy farming but on livestock systems as a whole. In the same way, when I as a consultant go to advise a farmer, I have to look at the entire farm and take multiple factors into account. Having been part of SOLID is very useful in that respect, because we have been looking at farm systems and analyzing complex entities. That experience helps me a lot.

Can you use your knowledge on low-input farming as an advisor?

Marco Horn: Some of the farmers are interested in low-input farming and there is an increasing interest in it. But my current job is not to transform all the Austrians farms to low-input farming. It’s an option they have and I can give valuable advice on that. However, I´m not supposed to be a missionary travelling around the countryside to persuade the farmers to apply low-input strategies. As an advisor I just provide options. The farmers have to make the decisions themselves.

A study conducted by breeding experts within the SOLID project has identified a number of genotypes as specificly suited for organic and low-input  dairy systems.  In the study, these genotypes are compared with conventional breeds.

By Marco Horn, Conrad Ferris, Auvo Sairanen, Mogens Vestergaard, Andreas Steinwidder, Werner Zollitsc, WP2

Conventional dairy cow types have been bred by selecting primarily for milk production within high concentrate input systems. In these systems forages, especially pasture, typically account for less than 50 % of the total ration. Therefore dairy cows arising from these breeding programmes are often perceived unsuitable for organic and low input milk production systems.

While farmers have identified a number of breeds and strains as being ‘adapted’ to low input systems, there is little scientific evidence to prove that these breeds are more appropriate than conventional genotypes. However, it is well known that cows used within any production system need to be suitable for that system in order to realise their full potential.

SOLID-Task 2.2 seeks to improve the competitiveness of organic and low input dairy production by understanding how contrasting genotypes adapt to a systematic restriction of nutrient and energy supply.

Consequently, a number of genotypes identified as being adapted to organic and low input systems by producers were compared with conventional breeds in studies undertaken in Austria, Finland and Northern Ireland.

Three experiments across Europe

To understand how contrasting genotypes adapt to a systematic restriction in nutrient and energy supply, three experiments (each of a 2 x 2 factorial design) were conducted: Factors comprised two diet types (normal (i.e. system-specific) levels or reduced quantities of energy and nutrients) to two cow genotypes (“conventional” versus “adapted”). The adapted dairy cow types represented different approaches to breeding for adaption:

Adaptation through selection for lifetime performance: a strain of Holstein cattle selected on low input farms for lifetime performance for more than 50 years (HFL) was compared with conventional Brown Swiss cattle (BS) in an organic, low-input milk production system within an alpine environment in Austria. Data from 30 and 21 lactations were included in the study for HFL and BS, respectively.

Adaptation through crossbreeding: 36 Swedish Red x Jersey x Holstein crossbred dairy cattle were compared with 36 conventional Holstein cows in an intensively managed grassland based system in Northern Ireland.

Adaptation through selection for fertility and health traits: 16 Nordic Red (Finnish Ayrshire) cows, which had been selected within a controlled multi-trait selection programme for over 30 years were compared with 32 conventional Holstein cows in a Finnish milk production system.

Within each experimental site, cows of each genotype were managed within one experimental herd. Half of the cows of each genotype were assigned to either a control diet or a diet in which concentrate inputs had been reduced by at least 40 % (low input).

First results

The experiments were completed in spring 2014 and the data are currently being analysed. Concentrate levels of the control and low input groups were 656 vs. 286 kg in Austria, 1657 vs. 717 kg in Northern Ireland and 2880 vs. 1359 kg in Finland. The preliminary data (only arithmetic means are presented) appear to confirm that a reduction in concentrate supplementation reduces milk solid yield, but does not have a detrimental effect on health and reproductive traits. The response of different genotypes to reduced nutrient and energy intakes were not consistent across the different studies. This is likely due to varying degrees of differences between both the genotypes studied and the feeding regimes implemented.

The next steps

A detailed statistical analysis of the data is currently being undertaken in each country. This will also include an examination of the blood and milk, in order to investigate metabolic response patterns. Furthermore a common dataset to permit an across-country analysis including several biomarkers is currently being prepared.

Read more about SOLID, WP2

AUTHORS

By Päivi Kurki and Arja Nykänen, WP1

On-farm research is an attractive method for farmers to test suitable farming practices in their own  environment. In cooperation with advisors and scientists, the topics are formulated taking wider views and theoretical background into account.

As part of SOLID WP1, on-farm research actions took place in Finland in 2013 in order to increase the protein self-sufficiency of organic dairy farms. This specific topic rose up in workshops held before the on-farm trials, and was also recognised as being important in other parts of Europe.

The trials covered two topics: on two farms the mixture of red clover and grass was topped and on two farms different mixtures of peas and cereals were tested. All participating farms were organic and located in eastern Finland, and the fields were moraine soils, which are quite warm with good water conditions, provided the structure of the field is not damaged.

Could grass topping increase the clover content?

A mixture of red clover (Trifolium pratense L.) and grasses (Phleum pratense L., Festuca pratensis L.) in the silage is the most common forage on Finnish organic dairy and beef farms, but the protein content of the first cut is often low because of low clover content.

The aim of the first two on-farm trials was to increase the protein content of the first cut of a mixed red clover and grass. The farmers wanted to put an observation to the test whether topping of grasses at an early stage could increase the relative competitiveness of red clover in the mixed ley.

The yield of clover-grass was measured by the farmer using his own machinery and by small plot measures of 0.25 m² carried out by a researcher. The yields and protein contents were compared between topped and non-topped areas.

Spring 2013 was warmer than average resulting in more vigorous and rapid early growth of red clover than usually. The swards were topped when the height of grass averaged 40 and 47 cm in the first and the second field, respectively. In the same fields, the height of red clover averaged 26 and 30 cm, respectively. Greater differences in height between grass and red clover than we found in 2013 had been observed by the farmers before. The apex height of timothy averaged 8 and 20 cm, respectively.

The idea was to cut timothy apex without damaging the red clover. This was not possible under these circumstances and it was decided to top at the height of 30 cm in both fields. The aim to increase the clover content of the yield by using topping was not met under these circumstances. Some successful experiences were obtained in other parts of Finland. The timing of topping in these trials was probably too late. Farmers might be interested to use this method more for green manure than for silage leys. Nevertheless the work stimulated interest in the farmers to test concepts on their own farms.

Optimal seed mixture for pea and cereals

The aim of the other on-farm trials was to find the most productive pea cereal mixture with a high pea – and consecutively protein – content. Pea cereal mixtures are cultivated to produce on-farm concentrates. They also provide a good break crop in the crop rotation since there is no clover in the mixture.

Five mixtures of peas (Pisum sativum L.) and cereals (spring wheat; Triticum aestivum L. or spring oats; Avena sativa L.) were tested on two organic dairy farms. The seed amounts in the mixtures varied from 150 to 270 kg/ha of pea and from 50 to 150 kg/ha of cereals and the yield and pea content in the yield were recorded.  The yields were measured by farmers using a combined harvester equipped with scales.

The optimum seed mixture was 200 kg ha^-1 of pea and 100 kg ha^-1 of spring wheat. The role of the cereals was to prevent the stand from lodging, but in some cases cereals also shaded the peas and smothered them out.

On-farm trials have a lot to offer

The on-farm experiments were relatively easy to carry out with help of good machinery and there was high interest by the farmers in the topics. The farmers were very keen on the results as the questions came from them and the answers were found on their own fields.

The discussion part before and after the experimental work is the most important phase in the on-farm participatory research. In this case, discussions took place together with farmers, advisors and researchers to define the questions, and to conclude from results and experiences afterwards.

Read more: Homegrown proteins in Finland

The trials showed examples of successful cooperation and networking of farmers, advisors and researchers. The aims to get more information for the farmers themselves and to disseminate it efficiently to other farmers by professional magazines, Internet and open field days were also met.

All in all, on the basis of the experiences from the trials in Finland, on-farm experiments have a lot to offer both farmers and researchers.

AUTHORS

At the 65^th Annual Meeting of the European Federation of Animal Science in Copenhagen, researchers from SOLID received the “Wageningen Academic Publishers Award” for a contribution from SOLID Work Package 2. 

The award-winning paper is titled “Reducing concentrate supplementation in an alpine low-input system: response of two dairy cow types“ and presents the results from a feeding trial conducted in Austria.

At the meeting in Copenhagen, Marco Holm received the award on behalf of himself and his colleagues.

Furthermore results from SOLID Work Package 2 were presented at

• the LfL Ökolandbau-Tag in Triesdorf, Germany, a conference focussing on applied research for organic farming,
• the first Joint Meeting of the FAO-CIHEAM Mountain Pastures, Mediterranean Forage Resources networks and Mountain Cheese network in Clermont-Ferrand, France
• the Internationale Weidetagung in Zollikofen, Switzerland, a conference focussing on pasture based dairying.